Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 60469 — Posen, IL

ZIP code 60469 (Posen, Cook County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 10 and the first fall frost November 1.

Where ZIP 60469 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone6a−10 to −5 °F

Coldest night−23.3 to −20.6 °C

Last frostApr 10

First frostNov 1

2012 zone6a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Posen, IL…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Posen, IL

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 10median — 50% chance of a later frost

Safe for tender plantsApril 26only 10% chance of frost after

First fall frostNovember 1median — 10% chance by Oct 21

Growing season203 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 1 and returns around November 11.

From the NOAA station Chicago Midway Airport 3sw, IL — 9 miles away, elevation 620 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 60469

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 27 – Mar 13

SpinachSow outdoors · Feb 27 – Mar 20

Broccoli, cabbageStart indoors · Jan 30 – Feb 13

Broccoli, cabbageTransplant · Mar 20 – Apr 3

Onion setsPlant outdoors · Mar 13 – Mar 27

PotatoesPlant outdoors · Mar 20 – Apr 3

LettuceSow outdoors · Mar 13 – Mar 27

Carrots, beetsSow outdoors · Mar 20 – Apr 3

TomatoesStart indoors · Feb 13 – Feb 27

TomatoesTransplant · Apr 17 – May 1

Peppers, eggplantStart indoors · Jan 30 – Feb 13

Peppers, eggplantTransplant · Apr 24 – May 8

BeansSow outdoors · Apr 17 – May 1

Sweet cornSow outdoors · Apr 17 – May 1

Cucumbers, squashSow outdoors · Apr 17 – May 1

Fall lettuce, spinachSow outdoors · Sep 6 – Sep 20

GarlicPlant cloves · Oct 18 – Nov 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 10) and first fall frost (Nov 1) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 60469 came on Mar 21 — 13 days earlier than the 1991–2020 average (Apr 3).

average
Apr 32026
Mar 21

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Soil in Posen, IL

The soil mapped at the center of ZIP 60469 is Bryce — silty clay, poorly drained.

TextureSilty clayholds water and nutrients; slow to drain and warm up

pH6.2slightly acidic; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter5.5%high

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Bryce silty clay, 0 to 2 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 60469; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Posen, IL

Summer high85 °Faverage high, July

Winter low20 °Faverage low, January

Hot days21days a year at 90 °F or more

Freezing nights108nights a year at 32 °F or less

Growing degree days3,592base 50 °F — the season’s usable heat

Longest day15 h 12 mindaylight on June 21

Shortest day9 h 09 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation41.5 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Chicago Midway Airport 3sw, IL (9 mi away); precipitation: Homewood 0.1 Ese, IL (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

604726a

Robbins, IL · 2 mi

604066a

Blue Island, IL · 2 mi

Midlothian, IL · 3 mi

Oak Forest, IL · 4 mi

Illinois planting zones →

Questions about 60469

What planting zone is ZIP code 60469?

ZIP code 60469 (Posen, IL) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Posen, IL?

The median last spring frost (32 °F) near 60469 is April 10; after April 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Chicago Midway Airport 3sw station.

When is the first frost in Posen, IL?

The median first fall frost near 60469 is November 1, giving a median frost-free growing season of 203 days.

When should I plant tomatoes in 60469?

Start tomato seeds indoors around Feb 13 – Feb 27 and set transplants outside around Apr 17 – May 1, one to three weeks after the median last frost.

How much rain and snow does 60469 get?

About 41.5 inches of precipitation a year (NOAA 1991–2020 normals, Homewood 0.1 Ese station).

How hot do summers get in Posen, IL?

The average high peaks at 85 °F in July, with about 21 days a year at 90 °F or more.

What kind of soil does 60469 have?

The USDA soil survey maps Bryce at the center of ZIP 60469: silty clay, poorly drained, pH about 6.2 (slightly acidic).

Did spring come early in Posen, IL in 2026?

Spring leaf-out near 60469 came on Mar 21 in 2026, 13 days earlier than the 1991–2020 average (Apr 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Posen, IL?

Long-day onions: the longest day near 60469 is 15 h 12 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).